Most Conservative MPs, including at least six members of the shadow cabinet, are sceptical about their party's continued focus on climate change policies, it has been claimed.

The recent furore around "Climategate" has hardened the views of Tory MPs, many of whom were already unconvinced by the scientific consensus, and has led to increasing calls for the issue to be pushed down the priority list.

Tim Montgomerie, founder and editor of the ConservativeHome website, said climate change had the potential to be as divisive for the party as Europe once was. "You have got 80% or 90% of the party just not signed up to this. No one minded at the beginning, but people are starting to realise this could be quite expensive, so opinion is hardening."

Montgomerie said that while some MPs simply did not believe the science, others felt it would harm the economy too much to focus on policies to reduce emissions. "Some think, 'What is the point in taking all these decisions if India and China and others row ahead?' Nigel Lawson makes the point that 30% of Indian people have no electricity and the Indian government has to give that to them. The cheapest way to do that is fossil fuels."

Lord Lawson chairs the Global Warming Policy Foundation, a thinktank that claims the climate debate has been distorted by exaggeration. On pages 28 and 29, Benny Peiser, director of the foundation, debates the issue with the Observer's science editor, Robin McKie. A recent BBC poll found that 25% of people did not think global warming was happening – compared with 15% in November – and a similar trend is taking place among Conservative MPs.

"You scratch almost any backbencher and you find they are sceptical and I know of six shadow cabinet ministers who are sceptical about the economic consequences of a low-carbon policy," said Montgomerie. He said the leadership was "recalibrating" its message.

Last week, representatives of 50 Tory councils gathered in London for a "Lean and Green" conference where Nick Herbert and Greg Clark – the shadow environment and energy secretaries – argued that green policies could save money and improve Britain's energy security. Clark rejected the notion that it was a change in direction. "There is a real threat to our energy security and there is a risk of a black-out," he said. Green policies that developed alternatives to fossil fuels and persuaded people to reduce energy consumption were "win-win" because they saved money, provided energy security and reduced carbon emissions.

One MP said the party was much more likely to respond to economic arguments: "There is a large group in the party – probably the majority – who are sceptical. That ranges from those who don't believe any of it to those that think the climate is changing but are not sure how much it is down to human beings, to those who accept the science but think we could act, but then in one year China and India could wipe out that effort. "

There are fears that the issue could flare up after the election if the Conservatives win power – particularly around plans for a third runway at Heathrow, which the party has said it will scrap.

Tim Yeo, the Tory MP who chairs the environmental audit select ­committee, said the shift had come about because of scientific mistakes, and a "backwash" from Copenhagen. "That has created a context in which it is easy for sceptics to build momentum and that is influencing a good number of politicians.

"What people have lost sight of is that serious climate-change scientists have always argued that the climate is changing gradually, that temperatures are rising and that one factor – and probably the main one – is the increase in greenhouse gases in the atmosphere. But they have never argued that it is easy to know how quickly that is happening.

The scientist at the centre of "Climate­gate" last night revealed he was so traumatised by the scandal that he considered killing himself. Professor Phil Jones told the Sunday Times the support of his family, especially the love of his five-year-old granddaughter, had helped him to shake off suicidal thoughts.